1. Field of the Invention:
This invention relates to generally to dispensers for paste-like products, and more specifically an arrangement for delivering and guiding a paste from a flexible storage container accommodated in a dimensionally stable container (xe2x80x9cpotxe2x80x9d) downwards into a dispenser operating by reduced pressure.
2. Discussion of the Related Art:
Liquid to paste-form detergents are known in large numbers. They are generally formulated to meet domestic requirements, i.e. they are expected to be sufficiently liquid so that they can be poured out and measured/dosed without difficulty. Since, in addition, they are expected to be stable in storage over a relatively broad temperature range, the use of organic solvents and/or hydrotropic additives cannot normally be avoided. However, such additives do not contribute to the actual washing process, are comparatively expensive and, in addition, take up packaging space and transportation and storage capacity. The presence of flammable solvents is particularly troublesome and necessitates additional safety precautions on account of the relatively high consumption of detergents in laundries. Because of this, detergent concentrates of the type mentioned can only be used to a limited extent, if at all, in laundries.
Accordingly, powder-form detergents are mainly used in laundries. Since the exact dosing of powder-form detergents is problematical or labor-intensive, particularly in large and extensively automated laundries, the detergents are mostly stored and dispensed in predissolved form as stock liquors, i.e. a water-based concentrate is prepared and delivered to the individual points of consumption. However, the detergents typically used in laundries contain comparatively high levels of washing alkalis which are only soluble to a limited extent in cold water and, in addition, lead to so-called salting-out effects. They promote phase separation with the result that the organic components, more especially the nonionic surfactants and soaps, separate and cream up. Accordingly, the concentrates have to be diluted relatively heavily with water and, in addition, the stock liquors have to be constantly and intensively mixed and circulated to prevent individual components from being deposited in the feed lines to the points of consumption. Processes such as these require considerable investment in large mixing vessels and the associated static mixers and feeders and also a constant supply of energy for the heating and circulation of the stock liquors.
A detergent which meets these requirements is proposed in EP 0 295 525. This detergent is a paste which imposes particular demands on handling for the purpose of dosing and mixing with water as solvent. Detergent pastes such as these are transported and stored in large containers. It is proposed to place this storage container in a removal pot above the dispenser and to guide the paste downwards. In cases where a flexible container is used, it is proposed to place a follower plate on the container in the pot, this follower plate applying pressure to the storage container in order to ensure substantial emptying thereof. A corresponding arrangement is described in the specification.
It has been found that the follower plate has to be made very heavy to ensure uniform lowering and substantial emptying of the storage container. However, the disadvantage of this is that such heavy weights are difficult to handle so that the risk of errors in operation is increased. In addition, an overall very stable and hence expensive construction is required for the arrangement.
The technical problem addressed by the present invention is to further develop the known arrangement for a paste dispenser in such a way that the storage container is safely and substantially completely emptied by simple means. The solution to this problem provides in one embodiment of the invention that the pot is sealed off from the dispenser, the follower plate is sealed off from the pot and is movable therein; and a reduced pressure is applied between the pot and the flexible storage container.
The effect of this embodiment of the invention is that, without significant outlay and with simple means, atmospheric pressure is applied to the follower plate through the reduced pressure or suction applied to flexible storage container, so that the follower plate applies a pressure to the flexible storage container so uniformly that the follower plate is uniformly lowered to ultimately provide substantially complete emptying of the pot. The uniform lowering of the follower plate is advantageously be enhanced by the relative large width or height of its edges to prevent tilting in this way. If the space between the pot and the flexible storage container is connected to the suction side of the injector, the reduced pressure can be generated without any need for additional means.